1. Technical Field
The present disclosure relates generally to crosslinked polymers formed from at least two precursors, and more particularly to crosslinked polymers where the crosslinker or one of the precursors is a therapeutic agent which can be released in its original, unmodified form upon degradation of the polymer material. Methods of preparing and uses for such crosslinked polymers are also described.
2. Background of Related Art
In the field of medicine there has been a growing recognition of the benefits of using crosslinked polymers and biomaterials for the treatment of local diseases. Local diseases are diseases that are manifested at local sites within the living animal or human body, for example atherosclerosis, postoperative adhesions, rheumatoid arthritis, cancer, and diabetes. Crosslinked polymers may be used in drug and surgical treatments of such diseases.
Historically, many local diseases have been treated by systemic administration of drugs. In this approach, in order to achieve therapeutic levels of drugs at local disease sites, drugs are delivered (via oral administration or injection) at a high systemic concentration, often with adverse side effects. As an alternative, locally implanted crosslinked polymers or biomaterials may be used as carriers to deliver drugs or therapeutic agents to local sites within the body, thereby reducing the need for the systemic administration of high concentrations of such drugs or therapeutic agents.
However, upon degradation of such locally implanted crosslinked polymers or biomaterials, the drug or therapeutic agent may be released as a modified molecule. Although the release of a modified drug molecule may provide some therapeutic effect, it would be beneficial to provide crosslinked polymers or biomaterials which upon degradation, release a drug or therapeutic agent in its original, unmodified form, e.g., without end-capping, which may maximize the therapeutic effect of the agent.
Moreover, if a precursor of the polymer or biomaterial is itself the therapeutic agent [e.g., the crosslinking agent], then the mechanism of sustained local release is built into the implanted crosslinked polymer or biomaterial. As the crosslinked polymer degrades over time, the therapeutic agent will be released in a sustained manner.